Re: how to properly verify a broadcast to multicast-helper?

Hi,

Have a look on the IE blog, it discusses the test options and config. Great
detail there.

http://blog.internetworkexpert.com/2008/05/06/understanding-the-ip-multicast-helper-map-command/

Cheers.
--------------------------------------------------
From: "Wouter Prins" <wp_at_null0.nl>
Sent: Monday, May 25, 2009 7:48 PM
To: "Cisco certification" <ccielab_at_groupstudy.com>
Subject: how to properly verify a broadcast to multicast-helper?

> hey all,
>
> i was wondering how you can verify a broadcast to multicast helper-map? i
> labbed this up and i noticed that i cannot send an ip sla with a udpecho
> to
> the broadcast address (255.255.255.255) as this is disallowed.
>
> So i thought i would send the udpecho to the ip broadcast address of that
> subnet: 174.1.26.255 and it is properly send out:
>
> *Mar 1 02:22:52.391: UDP: Random local port generated 49538, network 1
> *Mar 1 02:22:52.395: Reserved port 49538 in Transport Port Agent for UDP
> IP
> type 1
> *Mar 1 02:22:52.395: UDP: sent src=174.1.26.6(49538),
> dst=174.1.26.255(3434), length=24
>
> Now on the router configured for the broadcast to multicast conversion i
> configured the following on the interface receiving these udpecho's:
>
> RSRack1R2#
> interface FastEthernet0/0
> description "facing ip sla router"
> ip address 174.1.26.2 255.255.255.0
> ip broadcast-address 174.1.26.255
> ip pim sparse-mode
> ip multicast helper-map broadcast 226.26.26.26 100
> no ip mroute-cache
> end
> interface Serial1/0
> description "this interface should have the converted broadcast"
> ip address 174.1.23.2 255.255.255.0
> ip pim sparse-mode
> no ip mroute-cache
> frame-relay map ip 174.1.23.3 203 broadcast
> no frame-relay inverse-arp
> end
>
> RSRack1R2#show access-list 100
> Extended IP access list 100
> 10 permit udp any any eq 3434
> RSRack1R2#show run | incl forward
> ip forward-protocol nd
> ip forward-protocol udp 3434
> RSRack1R2#show deb
> Generic IP:
> IP multicast packets debugging is on
> UDP:
> UDP packet debugging is on
> RSRack1R2#
> RSRack1R2#show ip pim rp-hash 226.26.26.26
> RP 150.1.1.1 (?), v2v1
> Info source: 150.1.3.3 (?), elected via Auto-RP
> Uptime: 01:35:23, expires: 00:02:53
> PIMv2 Hash Value (mask 0.0.0.0)
> RP 150.1.1.1, via Auto-RP
> RSRack1R2#show ip rpf 150.1.1.1
> RPF information for ? (150.1.1.1)
> RPF interface: Serial1/0
> RPF neighbor: ? (174.1.23.3)
> RPF route/mask: 150.1.1.0/24
> RPF type: unicast (ospf 1)
> RPF recursion count: 0
> Doing distance-preferred lookups across tables
> RSRack1R2#
>
> I dont see any packets being forwarded (RP-mappings are fine and no RPF
> failures occuring).
>
> Anyone who has a better idea on verifying this and perhaps why this is not
> working? :)
>
> --
> Wouter Prins
> wp_at_null0.nl
> 0x301FA912
>
>
> Blogs and organic groups at http://www.ccie.net
>
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Received on Tue May 26 2009 - 07:36:52 ART